(BQ) Part 2 book Chest radiology has contents: Miscellaneous cluster, positron e mission tomography computed tomography, diverse conditions, pediatric chest, esophagus, mediastinum, heart,.... and other contents.
chapter Heart Roshan Lodha Pericardial Effusion Pericardial sac normally contains 15 to 50 ml of pericardial fluid Pericardial effusion is an abnormal accumulation of fluid in the pericardial cavity Excessive fluid accumulation leads to increased intrapericardial pressure and when this is enough pressure to adversely affect heart function, it is called cardiac tamponade Pericardial effusion usually results from a disturbed equilibrium between the production and re-absorption of pericardial fluid, or from a structural abnormality that allows fluid to enter the pericardial cavity Types of pericardial effusion are: a Transudative (congestive heart failure, myxoedema, nephrotic syndrome) b Exudative (tuberculosis, spread from empyema) c Hemorrhagic (trauma, rupture of aneurysms, malignant effusion) d Malignant (due to fluid accumulation caused by metastasis) Causes of pericardial effusion are: a Idiopathic b Inflammatory i Postmyocardial infarction (Dressler’s syndrome) ii Connective tissue disorders Heart c Infectious i Viral ii Bacterial iii Tuberculosis d Postsurgical/trauma e Radiotherapy f Malignancy i Primary, e.g pericardial mesothelioma ii Metastatic g Metabolic i Hypothyroidism Patient presents with chest pain, breathlessness, dyspnea on exertion A small effusion may be asymptomatic On chest X-ray very small pericardial effusion may not be evident but when large enough it presents like “water-bottle heart” (Fig 8.1) in which the cardiopericardial silhouette is enlarged and assumes the shape of a water bottle or flask clinically it can produce dullness to percussion called Ewart’s sign Fig 8.1 Heart appears as a globular enlargement giving a water bottle configuration 101 102 Chest Radiology Lateral chest X-ray may show an “Oreo Cookie Sign”: a vertical lucent line directly behind sternum (epicardial fat), behind this a vertical opaque line (pericardial fluid) and behind this a vertical lucent line (pericardial fat) Ultrasonography is diagnostic as it shows fluid between the visceral and parietal layers of pericardium Volume of fluid can be estimated USG can be used as a therapeutic modality to aspirate the pericardial fluid CT chest is also diagnostic (Fig 8.2) Tuberculous Effusions Diseases of the pericardium are clearly visualized on CT It detects thickening of the pericardium and calcification with a high degree of sensitivity and specificity and is an accurate method Fig 8.2 CT chest shows pericardial effusion Heart of demonstrating the extent and distribution of pericardial calcification CT also demonstrates the presence of additional pleural effusions or ascites (Figs 8.3A and B) Constrictive Pericarditis Constrictive pericarditis (CP) is stiffening or reduction in the elasticity of the pericardium, resulting in impaired filling of the heart The symptoms of CP include exercise intolerance, dyspnea, hepatic and renal failure, it appears insidiously Imaging findings of calcifications and thickening of the pericardium, may be present (Fig 8.4), but the reliable and important findings are related to the filling pattern of the heart Patients respond dramatically to a complete surgical pericardiectomy when it is performed early in the disease process; therefore, it is important to consider CP when making the diagnosis A B Figs 8.3A and B Pericardial effusion, pleural effusion and ascites in a 13-year-old female (A) CT chest shows pericardial effusion with few air pockets (postdrainage), the fluid thickness is up to 25 mm, outer layer of pericardium is thickened Bilateral pleural effusion is present (B) Free fluid is present in the perihepatic and paracolic gutters and pericholecystic area 103 104 Chest Radiology Fig 8.4 X-ray chest shows sharp cardiac margin with straightening of right heart border with roughening of cardiac outline as a result of pleuropericardial thickening in constrictive pericarditis Atherosclerosis Atherosclerosis is hardening of the arteries due to deposition of cholesterol and other fat substances within the walls of the arteries within a fibrous coat; these fatty deposits are called plaques Plaque builds up on the inner wall of the intima with secondary degeneration and fibrous replacement of media in the arteries (Figs 8.5A and B) It is a progressive disease more common in elderly and in males Atherosclerosis is a common disorder of the arteries and is leading cause of thoracic aortic aneurysm distal to left subclavian artery The other arteries frequently affected are the coronary arteries and the cerebral arteries Redundant and Tortuous Aorta Normal configuration of the aorta is maintained due to elasticity of its wall As age advances there is degenerative change in the elastic fibers of wall, it loses its elasticity and may become redundant and tortuous Patients usually remain asymptomatic Heart A B Figs 8.5A and B (A) Plain CT abdomen No clear demarcation is seen between the wall and lumen of aorta (B) Contrast CT abdomen clearly demarcates the aortic wall thickening and patent lumen On chest X-ray, it may appear as a widening of the mediastinum It may mimic aneurysm However, cross-sectional imaging confirms the nonaneurysmal tortuous configuration and redundancy of the aorta (Figs 8.6A and B) Thoracic Aortic Aneurysm A true aneurysm is defined as a localized dilatation of the aorta with 50 percent over the normal diameter and includes all three layers of the vessel, intima, media and adventitia Thoracic aortic aneurysms are less common than aneurysms of the abdominal aorta There are two major types of aneurysm morphology: fusiform and saccular A pseudoaneurysm or false aneurysm is a collection of blood and connective tissue outside the aortic wall, usually the result of a rupture 105 106 Chest Radiology A B Figs 8.6A and B Scout CT image of chest (A) shows prominent des cending aorta raising a suspicion of aneurysm Aortic reconstruction following contrast CT of chest and abdomen (B) shows no aneurysm but only tortuous and elongated dilatation of thoracic aorta The incidence of thoracic aortic aneurysm is estimated to be around six cases per lac patient years. Thoracic aneurysms occur most commonly in the sixth and seventh decade of life The vast majority of thoracic aneurysms are associated with atherosclerosis Male:female ratio is 3:1 Hypertension is an important risk factor, being present in 60 percent of patients Asymptomatic aneurysms are incidentally detected on routine X-ray chest The aortic aneurysm produces mediastinal widening or alters contour of the heart or aotic outline (Figs 8.7 and 8.8) Heart A B Figs 8.7A and B X-ray chest on penetrated AP projection (A) shows altered contour of distal thoracic aorta and (B) lateral view shows the aneurysmal dilatation of distal part of thoracic aorta A B Figs 8.8A and B (A) X-ray chest PA view of another case shows dilatation of distal thoracic aorta which is displaced to the left and is returning to its normal position at the level of diaphragm (B) Lateral view of thoracolumbar spine shows scalloping of the anterior margins of bodies of LV1 and LV2 107 108 Chest Radiology CT scan with intravenous contrast is a precise diagnostic tool in the evaluation of thoracic aneurysm The aneurysm size, extent of disease, presence of leakage and coincident pathology (Figs 8.9 and 8.10) are well demonstrated Magnetic resonance angiography is highly informative with multiplanar image reconstruction and visualization of extraluminal structures but disadvantage being limited availability, increased cost and lower resolution than traditional contrast angiography Coarctation of Aorta Coarctation of aorta is a congenital aortic narrowing in the region of the isthmus A B C Figs 8.9A to C Contrast-enhanced CT scan (A), and (B) axial sections, and (C) coronal reformatted image shows a large descending thoracic aorta aneurysm with a large com ponent of intramural thrombus (arrows) which shows no contrast uptake Calcification is present in the wall abutting the thrombus (arrow) in (A) Heart Fig 8.10 Thoracoabdominal aortic angiogram shows a fusiform aneurysm proximal to the origin of renal arteries and extends to just above the abdomen The dilatation of distal thoracic aorta seen on X-ray film is actually the redundant aorta There is a characteristic shelf-like narrowing of the aorta which usually occurs just beyond the origin of the left subclavian artery (Figs 8.11A to D) The severity of coarctation or narrowing can vary considerably and it is this severity which determines the age of presentation (Figs 8.11E to G) It is more common in males (M:F = 4:1) and is rare in blacks The collateral circulation distal to the coarctation is through the subclavian arteries and its branches like internal mammary artery to intercostals, scapular artery to anterior spinal artery, transverse cervical artery to lateral thoracic artery 109 ... unilateral Chest X-ray showing notching of posterior ribs bilaterally most prominent along inferior borders is likely a case of aortic coarctation 111 1 12 Chest Radiology Fig 8. 12 X-ray chest shows... neuroblastoma arise from the 127 128 Chest Radiology A B Figs 9.8A and B (A) Posterior mediastinal mass seen incidentally on chest roentgenogram in a weeks old female infant CT chest at the level of... Schw annomas have attenuation similar to that of muscles on CT scans 125 126 Chest Radiology A B Figs 9.5A and B X-ray chest PA and lateral views show a right welldefined paratracheal mass on